edk2/SOURCES/edk2-OvmfPkg-PlatformInitLib-limit-phys-bits-to-46.patch
2023-11-08 12:25:58 +00:00

54 lines
2.0 KiB
Diff

From b1643b16a4a70ea576b5f90476fd9c59750eafe8 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Thu, 1 Jun 2023 09:57:31 +0200
Subject: [PATCH 07/12] OvmfPkg/PlatformInitLib: limit phys-bits to 46.
RH-Author: Gerd Hoffmann <kraxel@redhat.com>
RH-MergeRequest: 41: enable dynamic mmio window
RH-Bugzilla: 2174749
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Commit: [1/2] d08a95b72276cba504176b3837714db67122ed66 (kraxel/centos-edk2)
Older linux kernels have problems with phys-bits larger than 46,
ubuntu 18.04 (kernel 4.15) has been reported to be affected.
Reduce phys-bits limit from 47 to 46.
Reported-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit c1e853769046b322690ad336fdb98966757e7414)
---
OvmfPkg/Library/PlatformInitLib/MemDetect.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
index 86700fc028..aab266399f 100644
--- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c
+++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
@@ -646,16 +646,19 @@ PlatformAddressWidthFromCpuid (
));
if (Valid) {
- if (PhysBits > 47) {
+ if (PhysBits > 46) {
/*
* Avoid 5-level paging altogether for now, which limits
* PhysBits to 48. Also avoid using address bit 48, due to sign
* extension we can't identity-map these addresses (and lots of
* places in edk2 assume we have everything identity-mapped).
* So the actual limit is 47.
+ *
+ * Also some older linux kernels apparently have problems handling
+ * phys-bits > 46 correctly, so use that as limit.
*/
- DEBUG ((DEBUG_INFO, "%a: limit PhysBits to 47 (avoid 5-level paging)\n", __func__));
- PhysBits = 47;
+ DEBUG ((DEBUG_INFO, "%a: limit PhysBits to 46 (avoid 5-level paging)\n", __func__));
+ PhysBits = 46;
}
if (!Page1GSupport && (PhysBits > 40)) {
--
2.39.3